linux加载驱动的两种makefile文件
加载驱动过程中,需要个Makefile文件来完成编译的命令。自己经常把把Makefile里面的命令搞混,这次,专门的研究了一下Makefile文件里面的东东,特写出来和大家分享一下
一 一个简单的驱动程序例子:
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/*======================================================================
A kernel module: book
This example is to introduce module params
The initial developer of the original code is Baohua Song
<author@linuxdriver.cn>. All Rights Reserved.
======================================================================*/
#include <linux/init.h>
#include <linux/module.h>
MODULE_LICENSE("Dual BSD/GPL");
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static char *book_name = "dissecting Linux Device Driver";
static int num = 4000;
static int book_init(void)
{
printk(KERN_INFO " book name:%s/n",book_name);
printk(KERN_INFO " book num:%d/n",num);
return 0;
}
static void book_exit(void)
{
printk(KERN_INFO " Book module exit/n ");
}
module_init(book_init);
module_exit(book_exit);
module_param(num, int, S_IRUGO);
module_param(book_name, charp, S_IRUGO);
MODULE_AUTHOR("Song Baohua, author@linuxdriver.cn");
MODULE_DESCRIPTION("A simple Module for testing module params");
MODULE_VERSION("V1.0");
二 Makefile文件有两种写法:
一种是:
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# Add your debugging flag (or not) to CFLAGS
ifneq ($(KERNELRELEASE),)
obj-m := boot.o
else
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
default:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
endif
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另外一种是:
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# Add your debugging flag (or not) to CFLAGS
ifneq ($(KERNELRELEASE),)
obj-m := boot.o
else
KERNELDIR ?= /usr/src/linux-headers-2.6.38-8-generic
PWD := $(shell pwd)
default:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
endif
比较两者可以发现,该两个Makefile的唯一差别是KERNELDIR的不同